1. Field of the Invention
The present invention relates to an oven in accordance with the introduction to the main claim.
The heating elements positioned in the oven cavity tend to heat both the cavity walls and each item positioned therein by heat transfer by natural convection, by forced convection using a cooking fan, or by irradiation. Heat convection is by heat transfer from the heating elements and from the heated physical parts of the oven to the air present within the oven cavity, and optionally by the operation of a cooking fan. Heat irradiation is by the infrared radiation emitted by the heating surfaces and heated surfaces towards the cooler surfaces, for example those of the food.
The cabinet in which the oven is installed is cooled by a cabinet cooling fan, external to the cavity.
That heat portion transferred by irradiation is more effective for food browning or grilling than that due to convection. In particular, irradiation enables the heat to penetrate less into the food than the heat transmitted by convection, but facilitates surface browning of the food relative to its degree of internal cooking.
2. Description of the Related Art
A drawback of known cooking methods is that a food placed in the oven cavity can exceed the point of optimum internal cooking, reached on termination of the cooking process, if it remains in the closed cavity after deactivation of the heating elements present therein.
Moreover, after removal of the food from the oven cavity, this latter remains hot for a considerable time period. This condition prevents rapid cleaning of the oven by the user. The condition also delays use of the oven for preparing another food if this requires cooking temperatures less than those used in the previous cooking/cleaning process.
There is also the problem that if the oven has been switched off but its cavity and closure door are still hot, persons, in particular children, can suffer burns if they come into contact with it even several minutes after switch-off.
The state of the art also comprises ovens in which a condensate exit stack is present, connected between the cavity and the cabinet cooling system (in particular, the ventilation channel), this stack conveying the now heated cooling air to the outside of the oven. A movable closure device is provided on this stack. Such ovens do not enable fresh air to be withdrawn and fed into the oven, i.e. taken directly from the environment outside the oven, as the air flow flows only towards the outside of the cavity (normally entrained by the venturi effect); this flow is in the form of air which is not fresh as it has already been used to cool the cabinet.